The Fourth Annual Dow Chemical Graduate Research Symposium 2015 September 21, 2015

William G. Lowrie Department of Chemical and Biomolecular Engineering The Ohio State University

Abstract List by Category

A. Bioengineering and Biotechnology

1. High efficiency production of poly (malic-acid) from sugarcane juice by Aureobasidium pullulans

2. Controlled Oxygenation of Hepatic Hollow Fiber Bioreactors via Mixtures Polymerized Hemoglobin Based Oxygen Carriers

3. Application of Polymerized Hemoglobin to Chronic Wounds to Accelerate Wound Healing

4. Detection of Human Papillomavirus 16 in Squamous Cell Carcinoma of the Head and Neck

B. Catalysis and Reaction Engineering

1. Methane to methanol conversion: Using paired acid sites in microporous materials

2. Carbon Monoxide and Hydrogen Sulfide Poisoning on Nitrogen Doped Carbon: a Density Functional Theory Study

3. Hydrodechlorination of Trichloroethylene over Swellable Organically-modified Silica (SOMS)

4. Designing Microenvironments to Promote Enantioselectivity of Organocatalysts

5. Oxygen Reduction Reaction (ORR) Performance of Nitrogen-containing Carbon Nanostructures (CNx) and Iron-Nitrogen-Carbon (FeNC) Catalysts in Acidic Media

6. Steam Oxidation Studies of Fe2O3-based Oxygen Carriers Using Al2O3, MgAl2O4 and TiO2 as Support Materials for Chemical Looping Gasification

7. Multiscale Modeling of Reduction Chemistry on PdO surfaces

C. Colloids, Aerosols, and Surfaces

1. Enhanced growth of n-propanol nanodroplets in the free molecular regime

D. Polymers, Nanomaterials, and Membranes

1. Fabrication of High Flux Spiral-wound Membrane Module for Efficient Gas Separation

2. Synthesis and Characterization of Polyethersulfone Membrane as Composite Membrane Support Material via Phase Inversion Technology

3. Fabrication of Thin-Film Composite Membranes: A Technology Scale-up

4. 2-Stage Hybrid Membrane Process for CO2 Capture from Flue Gas in Power Plants

5. Nanoparticle loaded non-spherical block copolymer micelles generated by interfacial instability (emulsion) process

6. Molecular Dynamics of Coarse-grained Ionomers Showing Aggregate Morphology During Deformation

7. Molecular Dynamics Simulations of Microphase Separating Tapered Diblock Copolymers

E. Energy and Sustainability

1. Effect of confinement on sorption behavior of ethane in Nanoporous Silica

Bioengineering and Biotechnology

A.1

High efficiency production of poly (malic-acid) from sugarcane juice by Aureobasidium pullulans

Chi Cheng

Advisors: Shang-Tian Yang

Poly(L-malic acid) (PMA) is a polymer with great potential in biomedical applications. Its monomer, malic acid (MA), is a widely used food acidulant and has huge commercial value. Industrial sugarcane juice was studied for PMA and MA production by Aureobasidium pullulans ZX-10. Sugarcane juice can be used as a desirable medium for PMA production without any pretreatment, addition of nitrogen or metal salts. Fermentation time from sugarcane juice (110.5 hr) is much shorter compared to pure sucrose (220.5 hr). A PMA production at titer equivalent to 122.0 g/L MA was achieved in fed-batch fermentation with a sugar concentration about 120 g/L in sugarcane juice. Higher productivity was achieved by repeated-batch fermentation by cell-recycle, in the second and third batch, productivity increased 32% (0.665 g/(L·h)) and 85% (0.934 g/(L·h)) compared to the first batch (0.505 g/(L·h)). These results show that sugarcane juice is an efficient renewable feedstock for PMA and MA production, while operating modes such as fed-batch and repeated-batch fermentation can be used to achieve higher titer or productivity.

A.2

Controlled Oxygenation of Hepatic Hollow Fiber Bioreactors via Mixtures Polymerized Hemoglobin Based Oxygen Carriers

Donald Belcher

Andre Palmer

Hepatic hollow fiber bioreactors are a potential bioartificial liver assist device (BLAD). The operations of these types of devices are limited by the oxygen transport to hepatocytes in the extra-capillary space (ECS). Hemoglobin based oxygen carrier (HBOC) enhanced media can increase oxygen delivery to hepatocytes. This study seeks to evaluate how varying ratios of relaxed and tense state polymerized HBOC mixture enhanced media can modulate the oxygen gradient in the ECS. Mixtures of glutaraldehyde polymerized tense and relaxed state hemoglobin were prepared; biophysical properties of the resultant mixtures were then analyzed. A finite element analysis was performed using the determined biophysical properties to evaluate the dissolved oxygen gradient and oxygen flux across the membrane. We expect that total HBOC concentration, HBOC ratios, inlet flow rate, and inlet oxygen tension can be varied to control both the oxygen gradient in the ECS and the total oxygen flux into the ECS.

A.3

Application of Polymerized Hemoglobin to Chronic Wounds to Accelerate Wound

Healing

Kristopher Richardson

Andre Palmer

Oxygen plays a vital role in the continuous wound healing process, since immune cells at the wound site rely on oxygen for cellular respiration. If the population of immune cells is reduced at the wound site, the wound healing process can be extended for a longer period of time, eliciting the formation of a chronic wound. In the United States, approximately six million people are affected by chronic wounds annually. Hemoglobin (Hb), the protein that transports and delivers oxygen in the body, has been topically applied to chronic wounds to accelerate wound healing. It has been hypothesized that the mechanism that leads to accelerated wound healing is the ability of Hb to facilitate oxygen transport. It has also been hypothesized that Hb may exert therapeutic effects by promoting a pro-healing, anti-inflammatory macrophage phenotype at the wound site, leading to accelerated wound healing in chronic wounds. We hypothesize that by engineering the oxygen affinity of hemoglobin-based oxygen carrier mixtures of tense state and relaxed state polymerized hemoglobin we will be able to identify the exact role each mechanisms plays in healing chronic wounds.

A.4

Detection of Human Papillomavirus 16 in Squamous Cell Carcinoma of the Head and Neck

Kyoung-Joo Jenny Park

Jeffrey Chalmers

Head and neck squamous cell carcinoma (HNSCC) is the most common form of head and neck tumor. Among various causative factors, human papillomavirus (HPV) accounts for 70% of the oropharyngeal cancers that involve tonsils or base of the tongue. Investigating the HPV expression in circulating tumor cells (CTCs) provides specific opportunities because this agent has unique characteristics and a moderately-understood life cycle, which has been linked to different stages of the disease progression. Combined with the negative enrichment and RNA in situ hybridization technique, difficulties in analyzing mRNA targets in CTCs are overcome, and visualization of the HPV 16 markers on individual cells is achieved. Experimental results show accuracy, specificity, and precision of the methodology, as well as the limitations with current technology. This study can provide understanding of the mechanism of the tumorigenesis of HPV-associated HNSCC and potentially the role of CTCs in general.

Catalysis and Reaction Engineering

B.1

Methane to methanol conversion: Using paired acid sites in microporous materials

Nitish Deshpande

Nicholas A. Brunelli

Methanol is an ideal intermediate for utilizing the abundant methane to produce value added products. Current catalysts are incapable of selectively converting methane to methanol, and the industrial process requires multiple energy intensive steps to achieve this reaction. Creating a catalyst capable of low temperature, highly selective oxidation would be industrially important. In nature, particulate methane mono-oxygenase (pMMO) enzymes catalyze this reaction under ambient conditions by employing a di-copper active-site. Recently, pMMO-inspired Cu-exchanged zeolites have been developed that can produce methanol at low temperatures with high selectivity (~98%). Their inability to give closed catalytic cycles and the low yield (10-15  𝜇mol methanol/g catalyst) obtained because of the low concentration of the paired-Cu active-sites (~5-10%) in these catalysts limits their applicability on an industrial scale. Thus, this project will create novel synthetic methods to create a high density of paired-Cu active-sites through synthesizing uniform paired acid sites in microporous materials.

B.2

Carbon Monoxide and Hydrogen Sulfide Poisoning on Nitrogen Doped Carbon: a Density Functional Theory Study

John Borror

Aravind Asthagiri

Current technology for proton exchange membrane fuel cells relies on platinum as a catalyst for oxygen reduction. One alternative to platinum is nitrogen doped carbon materials (CNx). One of the problems with CNx materials is that the exact catalytic site is not known. We developed a model of these nitrogen doped carbon materials. Then we performed density functional theory calculations to investigate the adsorption of CO and H2S on nitrogen doped carbon. Experimentally CNx materials are not poisoned by CO and H2S while platinum and Fe-CNx materials are poisoned. By comparing our model with these experimental results we narrowed down the number of possible catalytic sites for these materials. CNx materials have the potential to reduce the cost associated with PEM fuel cells.

B.3

Hydrodechlorination of Trichloroethylene over Swellable Organically-modified Silica (SOMS)

Gokhan Celik

Umit S. Ozkan

Groundwater contamination by trichloroethylene (TCE) is an environmental concern due to its toxicity level and its impact on groundwater. Hydrodechlorination of TCE appears to be an efficient and cost effective alternative way of decontaminating groundwater. Although promising catalytic activities have been obtained with the palladium-based state-of-the-art catalysts, deactivation due to reduced sulfur and chlorine species (SO4

2-, HS-, Cl-) is still a recurring issue. To overcome this issue, we are planning to use a newly-developed material, swellable organically modified silica (SOMS) as a catalyst support. The deposition of the active metal inside the pores has been facilitated by organometallic precursors used for catalyst synthesis. Hydrophobicity plays an important role to protect the active sites from ionic contaminants. Herein, use of SOMS as a scaffold for Pd-based catalyst is investigated for hydrodechlorination of TCE reaction. Activity measurements performed in liquid and gas phases as well as characterization results will be presented.

B.4

Designing Microenvironments to Promote Enantioselectivity of Organocatalysts

Mariah Whitaker

Nicholas A. Brunelli

Intriguing small, metal-free organic molecules called organocatalysts are emerging as important highly selective materials. Like enzymes, organocatalysts are designed to utilize acid-base cooperative interactions to catalyze C-C bond forming reactions important for pharmaceutical synthesis. While highly useful, organocatalysts are typically employed at high concentrations, making product purification difficult and costly. We seek to create a heterogeneous version of these powerful homogeneous

catalysts. The key challenge is designing an immobilization strategy to ensure the highly enantioselective homogeneous catalysts can achieve high enantioselectivity as heterogeneous catalysts. By immobilizing an analog of the enantioselective Takemoto’s catalyst to mesoporous silica, high selectivity can be achieved by a heterogeneous catalyst with uniform active sites. In addition, further design of the microenvironment around the catalyst can allow our catalyst to perform cascade reactions with a single green solvent in a flow reactor, avoiding the need for costly purification of synthetic intermediates.

B.5

Oxygen Reduction Reaction (ORR) Performance of Nitrogen-containing Carbon

Nanostructures (CNx) and Iron-Nitrogen-Carbon (FeNC) Catalysts in Acidic Media

Kuldeep Mamtani

Umit Ozkan

In spite of significant research work towards the development of transition metal containing carbon materials as oxygen reduction reaction (ORR) catalysts for proton exchange membrane (PEM) fuel cells, the nature of their active sites remains debatable. There is evidence that metal is an integral part of an active site whereas other studies show that it is the pyridinic-N coordinated to the edge planes of carbon is the active site. The current study tries to shed light on this debate by studying the effect of acid-washing and sulfur treatment on iron-nitrogen coordinated catalysts supported on carbon (FeNC) and nitrogen doped carbon nanostructures (CNx). Surface and bulk characterization experiments were also performed to gain valuable insights into these materials. Our results suggest that metal is an essential part of an active site for FeNC catalysts whereas it remains encased within the carbon nanostructure for CNx ones, hence not participating in ORR.

B.6

Steam Oxidation Studies of Fe2O3-based Oxygen Carriers Using Al2O3, MgAl2O4 and TiO2 as Support Materials for Chemical Looping Gasification

Ankita Majumdar

Liang-Shih Fan

Chemical looping gasification is an efficient, economic and sustainable means for electricity and/or chemicals production with inherent CO2 sequestration ability. It is based on the high temperature cyclic reduction and oxidation (redox) of metal oxide based oxygen carriers, producing CO2/syngas, H2 and heat in three separate reactors. This study investigates the steam oxidation performance of Fe2O3 based oxygen carriers using Al2O3, MgAl2O4 and TiO2 as support materials. Fixed bed steam oxidation of all the three oxygen carriers exhibited steam conversion values >75%, close to the thermodynamic predictions. XRD analyses reveal that different oxides of iron form complexes with TiO2 and Al2O3, while

no complexes are seen in the case of MgAl2O4. MgAl2O4-supported Fe2O3 oxygen carrier is further studied in a magnetic suspension balance with H2 reduction and steam oxidation for 20 redox cycles, where it exhibited excellent recyclability, with almost no drop in reactivity over time.

B.7

Multiscale Modeling of Reduction Chemistry on PdO surfaces Minkyu Kim

Aravind Asthagiri

Palladium oxide (PdO) thin film can grows on the Pd catalyst surface under oxygen rich applications. This PdO surface changes performance of Pd catalyst. To investigate the performance changes, the fundamental understanding of growth, decomposition and reactivity of the PdO surface is necessary. In this work, we study thermal reduction of PdO(101) surface which has been proposed to be important in Pd oxidation catalysis. To do this study, the Density Functional Theory calculation (DFT) and the kinetic Monte Carlo (kMC) simulation are used. Through the combination of DFT and kMC simulations for thermal reduction of PdO(101), we find autocatalytic behavior and oxygen vacancy chains during the thermal reduction of PdO(101) surface. These results agree qualitatively with the experiment results. Moreover, the results validate our previous claim that the autocatalytic behavior stems from the reduced phase which is not formed randomly but forms the oxygen vacancy chain.

Colloids, Aerosols, and Surfaces

C.1

Enhanced growth of n-propanol nanodroplets in the free molecular regime

Yensil Park, Shinobu Tanimura, and Barbara E. Wyslouzil

Barbara E. Wyslouzil

Investigations by Pathak et al. [Aerosol Sci. Technol., 2013, 14, 1310-1324] on the growth of nanodroplets in a supersonic nozzle, found that for nonane experimental and theoretical non-isothermal growth rates agreed quantitatively when condensation (qc) and evaporation coefficient (qe) were both equal to 1. In contrast, for D2O nanodroplets, quantitative agreement between experiment and theory during rapid particle growth was only achieved by reducing the evaporation coefficient to ~0.5 while maintaining qc = 1. One concern with the D2O experiment was that the droplets were highly supercooled, thereby introducing uncertainty into the analysis since the physical properties for D2O were extrapolated by up to 50K below the equilibrium melting point. Here we report on similar experiments conducted with n-propanol under conditions where droplets are not supercooled. As was observed for D2O, we find that setting qc=qe=1 yields theoretical droplet temperatures up to ~4K lower than those estimated from mass and energy balances, and growth rates that are distinctly below those

observed experimentally. Again, better agreement was found by setting qe=0.6 with qc= 1.0 or, alternatively, setting qc=~1.3 and qe = 1.0. Possible reasons for these differences will be discussed.

Polymers, Nanomaterials, and Membranes

D.1

Fabrication of High Flux Spiral-wound Membrane Module for Efficient Gas Separation

Witopo Salim

W.S. Winston Ho

Conventional spiral-wound membrane module has a drawback involving the feed gas “bypass” to the feed outlet (retentate) without flowing through the membrane, resulted in lower CO2 permeance than the flat-sheet membrane. Spiral-wound membrane module comprising face compression “O” rings for effective seal of gases was developed, including the spiral-wound membrane element, Plexiglas FRP (fiber-reinforced plastic) tube, and membrane housing. The membrane modules demonstrated essentially no leakage and the performances were evaluated at 57oC using dry feed gas and sweep gas flow rates of 1000 cc/min at 1.5 and 1 psig, respectively, before their humidification. The transport performance results obtained were CO2 permeance >700 GPU and CO2/N2 selectivity >160, which are twice the CO2 permeance of the conventional spiral-wound membrane modules. The membrane module is useful for gas separations including post-combustion CO2 capture in power plants and the removal of CO2 and H2S from synthesis gas, H2-containing mixtures, and CH4-containing mixtures.

D.2

Synthesis and Characterization of Polyethersulfone Membrane as Composite Membrane Support Material via Phase Inversion Technology

Dongzhu Wu, Yang Han, Witopo Salim, Varun Vakharia and W.S. Winston Ho

W.S. Winston Ho

Nanoporous polyethersulfone (PES) membranes were prepared by polyethersulfone/N-methyl-2-pyrrolidone (NMP)/2-methoxyethanol (2-ME) casting solutions. With water as the coagulant, both of the vapor and non-solvent induced phase inversion processes were employed in a successive sequence with varied parameters. A detailed study of the effects of different parameters, including polymer concentration, 2-ME/NMP ratio, relative humidity, water vapor exposure time, and water coagulation bath temperature, was conducted in lab-scale experiments to determine the operation guidelines for pilot-scale continuous machine fabrication. 14-inch wide pilot-scale PES membranes were fabricated with a controlled morphology. Surface morphologies of both lab- and pilot-scale PES membranes were characterized by scanning electron microscopy (SEM). Various effects of the preparation parameters

on the lab- and pilot-scale membranes were compared. In addition, Zeolite-Y (ZY) nano-particles were deposited on the pilot-scale PES membrane with a controlled thickness and uniform coverage continuously. PES membranes deposited with ZY particles were applied as the substrate of composite membrane for CO2 capture from flue gas.

D.3

Fabrication of Thin-Film Composite Membranes: A Technology Scale-up

Varun Vakharia

W.S. Winston Ho

Globally, the membrane technology is witnessing a significant growth due to increasing research and development, and market production in chemical, pharmaceutical, biopharmaceutical and life sciences industries. Membranes for gas separation have developed from a laboratory curiosity to a commercial reality due to the low cost and energy efficient alternative for gas separation. Recently, there have been significant breakthroughs in the development of high-flux thin polymer membranes with desirable performance for hydrogen purification and carbon capture applications. This work demonstrates the scale-up fabrication of such membranes via a continuous roll-to-roll membrane fabrication process. Different coating techniques were successfully developed for the fabrication of thin-films (15 µm - 200 nm) on a porous polymer substrate. Composite membranes (14 inches wide and > 500 feet long) were successfully fabricated via the continuous roll-to-roll membrane fabrication process. These membranes demonstrated impressive performances in the industrial field test for the H2 purification and CO2-removal applications.

D.4

2-Stage Hybrid Membrane Process for CO2 Capture from Flue Gas in Power Plants

Yang Han

W.S. Winston Ho Presented herein is a 2-stage membrane separation process for capturing CO2 from flue gas in a power plant. In the process, the flue gas stream flows to a vacuum membrane stage using a membrane with high CO2/N2 selectivity and moderate CO2 permeance. The retentate gas then flows to an air-sweep membrane stage employing another membrane with high CO2 permeance but low CO2/N2 selectivity. The CO2 enriched sweep air is passed to the combustor in a power plant. This process shows the lowest cost for CO2 capture from flue gas in a power plant among various membrane performance properties evaluated.

D.5

Nanoparticle loaded non-spherical block copolymer micelles generated by interfacial instability (emulsion) process

Gauri Nabar

Jessica Winter

Encapsulation within self-assembled block copolymer micelles offers a way to deliver hydrophobic materials including diagnostic agents and drug molecules into the aqueous environment. The emulsion route of micelle synthesis distinguishes itself from other micellization techniques, such as direct dissolution and nano-precipitation; by its ability to micellize nearly all block copolymers yielding a wide range of micelle morphologies. At present, the exact mechanism of nanoparticle loading into non-spherical micelles is unknown. In our work, we have used kinetic trapping to obtain non-spherical micelles ranging from smooth cylinders to noded, branched and interconnected networks. We have studied the dispersion characteristics of nanoparticles with different geometries and surface chemistries inside these non-spherical micelles. Such studies can provide much-needed insight into the underlying nano-structure formation mechanism. In addition, the ability to selectively synthesize different nanoparticle-loaded morphologies without re-engineering the block copolymer can greatly enhance the utility of these multi-functional nanostructures in numerous varied applications.

D.6

Molecular Dynamics of Coarse-grained Ionomers Showing Aggregate Morphology During Deformation

Janani Sampath

Lisa Hall

Ionomers are polymers with a small fraction of charged monomers that have a wide range of applications from dental fixtures and packaging to actuators. We consider dense melts of ionomers and counterions with no solvent. An important aspect of their performance is the aggregation of ions, since ionic aggregates act to hold polymer chains together like temporary cross-links. Because of the size scales involved, it is difficult to obtain a complete 3D microscopic picture of polymer aggregation experimentally; typically the thickness of a sample used in transmission electron microscopy is such that multiple overlapping aggregates appear together. How aggregate structure changes under strain and affects mechanical properties is even less clear. We perform molecular dynamics simulations of ionomers of various architectures, and show aggregate morphology and scattering profiles. We apply uniaxial tensile strain and observe the aggregates align, in qualitative agreement with experimental findings. We also obtain stress-strain curves and will discuss effects of degree of neutralization of the ionomers.

D.7

Molecular Dynamics Simulations of Microphase Separating Tapered Diblock Copolymers

Youngmi Seo

Lisa M. Hall Tapered AB copolymers consist of pure A and B blocks separated by a middle block whose composition is a linear gradient from pure A to pure B (or from B to A for inverse taper). Prior experiments and theory suggest that one can use taper length as an adjustable parameter to control interfacial and phase behavior, and that tapers potentially make the bicontinuous double gyroid phase more accessible. Using a simple coarse-grained model, we perform molecular dynamics simulations to determine the polymer structure and dynamics as a function of taper length. Generally tapers are seen to increase miscibility and decrease lamellar spacing; the significantly smaller lamellar spacing for inverse tapers is explained in terms of their unique chain conformations. The diffusion and relaxation behavior are closely related to the chain conformations at interfaces. The effect of tapering on penetrant diffusion through one of the microphases will also be discussed.

Energy and Sustainability

E.1

Effect of confinement on sorption behavior of ethane in Nanoporous Silica

Sumant Patankar

David Tomasko

High content of higher hydrocarbons such as ethane in certain shales has provided cheap raw materials for petrochemical industries. Confinement behavior of ethane in controlled pore glass (CPG) with nominal pore sizes of 7.5 nm and 35 nm was studied through sorption isotherms and quasi-elastic neutron scattering (QENS) experiments. A magnetic suspension balance was used to measure the adsorption isotherms at 2 temperatures and over a wide range of pressures. The gravimetrically measured isotherms highlight key confinement effects through differences between isotherms for the two pore sizes. Behavior of ethane in the smaller pores was probed further using Quasi-elastic neutron scattering. By measuring the diffusion co-efficient and residence time, we were able to study the effect of pressure and transition to supercritical phase on the dynamics of confined ethane molecules. This study describes physical properties and interactions in the ethane-CPG system under the influence of temperature, pressure and pore-size.